Biological Case Against Downlisting the Whooping Crane and for Improving Implementation under the Endangered Species Act

The Whooping Crane (Grus americana; WHCR) is a large, long-lived bird endemic to North America. The remnant population migrates between Aransas National Wildlife Refuge, USA, and Wood Buffalo National Park, Canada (AWBP), and has recovered from a nadir of 15-16 birds in 1941 to ~540 birds in 2022. Two ongoing reintroduction efforts in Louisiana and the Eastern Flyway together total ~150 birds. Evidence indicates the U.S. Fish and Wildlife Service (USFWS) is strongly considering downlisting the species from an endangered to a threatened status under the Endangered Species Act (ESA). We examined the current status of the WHCR through the lens of ESA threat factors, the USFWS’s Species Status Assessment (SSA) framework, and other avian downlisting actions to determine if the action is biologically warranted. Our research indicates that WHCRs are facing an intensification of most threat drivers across populations and important ranges. The AWBP is still relatively small compared to other crane species and most birds of conservation concern. To date, only one avian species has been downlisted from an endangered status with an estimated population of \u3c3,000 individuals. Representation in terms of WHCRs historic genetic, geographic, and life history variation remains limited. Also, the lack of spatial connectivity among populations, reliance of the reintroduced populations on supplementation, and continued habitat loss suggest that WHCR populations may not be resilient to large stochastic disturbances. Given that reintroduced populations are not self-sustaining, neither supplies true redundancy for the AWBP. Proposed downlisting before recovery plan population criteria have been met is objectively unwarranted 3 and reflects USFWS inconsistency across ESA actions. Only by incorporating basic quantitative criteria and added oversight into ESA listing decisions can we avoid an action as misguided as downlisting the Whooping Crane without consideration of its recovery plan criteria or ostensibly its population ecology

Mitigating avian collisions with power lines through illumination with ultraviolet light

Collisions with anthropogenic structures by long-distance migrants and threatened and endangered species are a growing global conservation concern. Increasing the visibility of these structures may reduce collisions but may only be accepted by local residents if it does not create a visual disturbance. Recent research has shown the potential for ultraviolet (UV) light, which is nearly imperceptible to humans, to mitigate avian collisions with anthropogenic structures. We tested the effectiveness of two UV (390–400 nm) Avian Collision Avoidance Systems (ACASs) at reducing collisions at two 260-m spans of marked power lines at the Iain Nicolson Audubon Center at Rowe Sanctuary, an important migratory bird stopover location in Nebraska. We used a randomized design and a tiered model selection approach employing generalized linear models and the Akaike Information Criterion to assess the effectiveness of ACASs considering environmental (e.g., precipitation) and detection probability (e.g., migration chronology) variables. We found focal (assessed power line) and distal (neighboring power line) ACAS status and environmental variables were important predictors of avian collisions. Our top model suggests that the focal ACAS illumination reduced collisions by 88%, collisions were more likely at moderate (10–16 km/h) compared to lower or higher wind speeds, and collision frequency decreased with precipitation occurrence. Our top model also indicates that the distal ACAS illumination reduced collisions by 39.4% at the focal power line when that ACAS was off, suggesting a positive “neighbor effect” of power line illumination. Although future applications of ACASs would benefit from additional study to check for potential negative effects (for example, collisions involving nocturnal foragers such as bats or caprimulgiform birds drawn to insects), we suggest that illuminating power lines, guy wires, towers, wind turbines, and other anthropogenic structures with UV illumination will likely lower collision risks for birds while increasing human acceptance of mitigation measures in urban areas

Emissions of trace gases and aerosols during the open combustion of biomass in the laboratory

We characterized the gas- and speciated aerosol-phase emissions from the open combustion of 33 different plant species during a series of 255 controlled laboratory burns during the Fire Laboratory at Missoula Experiments (FLAME). The plant species we tested were chosen to improve the existing database for U.S. domestic fuels: laboratory-based emission factors have not previously been reported for many commonly-burned species that are frequently consumed by fires near populated regions and protected scenic areas. The plants we tested included the chaparral species chamise, manzanita, and ceanothus, and species common to the southeastern US (common reed, hickory, kudzu, needlegrass rush, rhododendron, cord grass, sawgrass, titi, and wax myrtle). Fire-integrated emission factors for gas-phase CO{sub 2}, CO, CH{sub 4}, C{sub 2-4} hydrocarbons, NH{sub 3}, SO{sub 2}, NO, NO{sub 2}, HNO{sub 3} and particle-phase organic carbon (OC), elemental carbon (EC), SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Cl{sup -}, Na{sup +}, K{sup +}, and NH{sub 4}{sup +} generally varied with both fuel type and with the fire-integrated modified combustion efficiency (MCE), a measure of the relative importance of flaming- and smoldering-phase combustion to the total emissions during the burn. Chaparral fuels tended to emit less particulate OC per unit mass of dry fuel than did other fuel types, whereas southeastern species had some of the largest observed EF for total fine particulate matter. Our measurements often spanned a larger range of MCE than prior studies, and thus help to improve estimates for individual fuels of the variation of emissions with combustion conditions